Generating linear or circular motion power using different technologies is known for centuries. There are many types of engines to accomplish this. Internal Combustion engines and Steam engines are few examples of linear reciprocating engines. While Internal Combustion engines mainly use fossil fuel steam engines use hydro power. In all such engines, the reciprocating motion generated by the linear movement of one or more pistons is converted to the circular motion with the help of a crankshaft assembly. The engine is generally integrated within the main product (or machine) and serves as the heart of the equipment. Such an engine can be used as an automobile engine, aircraft engine, locomotive engine, ship engine, power generator engine, etc.
With the diminishing fossil fuel resources and unabated increase in energy costs and environmental concerns, engines using alternate energy sources such as bio-fuel, solar power, wind power, electric power, stored power, etc. are being developed around the world. However, such engines have many limitations. Production of bio-fuel takes enormous resources and they still pollute the environment. They do not meet the ever increasing energy demand as well. Engines that use storage power sources like batteries or compressed air have energy density issues. Similarly, the solar power is not efficient. Added to all, the initial capital and subsequent maintenance costs for machines that use alternate energy sources are very high. Further, the electricity that is used to charge the batteries or to refill the compressed-air tank may be produced from a thermal power plant that is again a concern for environmental pollution. Hence, in the absence of a viable alternative, until now, switching to new technology by changing from traditional Internal Combustion engines has been a challenge.